KEY: N = data do not exist; R = revised; U = data are not available.
aRevenues paid by American travelers to U.S. and foreign flag carriers.
bDoes not include vessel operators whose primary area of operation is fishing, towing, passenger transport, ferrying, or crew boat utility service.
cIncludes commercial port, marina, and other employees; excludes employees of non-for-hire private businesses.
dEstimate based on established active jobs for licensed and unlicensed personnel aboard oceangoing ships of 1,000 gross-tons and over, privately owned and operated, government-owned ships under bare boat charters, ship managers and General Agency Agreement, supplemented by Military Sealift Command employment totals for ships with Civil Service crews.
eThe U.S. Coast Guard changed its methodology for counting the number of recreational boats.Figures cited represent number of numbered boats, not estimates as previously noted for 1960 and 1970.
fDoes not include intraterritorial traffic (traffic between ports in Puerto Rico and the Virgin Islands, which are considered a single unit).